Waiting list e ticket

My self and my wife booked e tickets in train no.22637 travel date 21.05.2016 pnr 4219463947 &4219463654. I also have e ticket for my grand son in the same train pnr 4632275622 with waiting list. We donot require separate berth for my grandson. If this wait listed ticket is not confirmed, is there any provision/ways to accomadate my grandson travel along with us. Please guide me to accompany my grand son along with us for journey